1. Field of the Invention
The invention relates to a semiconductor structure and a manufacturing method thereof. More particularly, the invention relates to a package carrier and a manufacturing method thereof.
2. Description of Related Art
A chip package provides a chip with proper signal and heat transmission paths and protects the chip structure. A leadframe often serves as a carrier of a chip when a conventional wire bonding technique is applied. As contact density in a chip gradually increases, the leadframe which is unable to further improve the contact density can be replaced by a package substrate which can achieve favorable contact density. Besides, the chip is packaged onto the package substrate by conductive media, such as metal conductive wires or bumps.
In the well-known common light emitting diode (LED) package structure, an LED chip need be packaged before the LED chip is used, and the LED chip generates a significant amount of heat when emitting light. Given the heat cannot be dissipated and continues to accumulate in the LED package structure, the temperature of the LED package structure is increasingly raised. As such, the overly heated LED chip may have luminance decay, shortened life span, or even permanent damages. Therefore, heat sinks are configured in the existing LED package structure, so as to dissipate heat of the LED chip.
The conventional package substrate is comprised of a plurality of patterned conductive layers and at least one insulating layer. The insulating layer is configured between two adjacent patterned conductive layers for electrical insulation. A thermal conductive block is fixed to a lower surface of the package substrate through an adhesive layer. In most cases, the LED chip is electrically connected to the package substrate, and heat generated by the LED chip can be conducted from the patterned conductive layers and the insulating layer to the thermal conductive block. Since the thermal conductivity of the adhesive layer and the insulating layer is unfavorable, thermal resistance increases when the heat generated by the LED chip is conducted from the insulating layer and the adhesive layer to the thermal conductive block, which leads to unsatisfactory heat dissipation. Hence, how to dissipate the heat generated by the LED chip to the external surroundings in an effective manner has become a focus to researchers and designers in this field.